Characterization of the<i>Acinetobacter baumannii</i>Fur regulator: cloning and sequencing of the<i>fur</i>homolog gene

Daniel, Catherine; Haentjens, StÃ©phanie; Bissinger, Marie-Christine; Courcol, RenÃ© J

doi:10.1111/j.1574-6968.1999.tb13375.x

Cited by 32 publications

(16 citation statements)

References 19 publications

(27 reference statements)

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“…These include: (i) the TetR and LysR proteins AdeN (ABUW_1731) and AdeL (ABUW_1338) [19]; (ii) two members of the Fur family, Fur (ABUW_3033) and Zur (ABUW_3741) [21, 22, 24]; and (iii) the MerR-like protein SoxR (ABUW_2555) [23]. …”

Section: Resultsmentioning

confidence: 99%

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Towards the complete proteinaceous regulome of Acinetobacter baumannii

et al. 2017

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The emergence of Acinetobacter baumannii strains, with broad multidrug-resistance phenotypes and novel virulence factors unique to hypervirulent strains, presents a major threat to human health worldwide. Although a number of studies have described virulence-affecting entities for this organism, very few have identified regulatory elements controlling their expression. Previously, our group has documented the global identification and curation of regulatory RNAs in A. baumannii. As such, in the present study, we detail an extension of this work, the performance of an extensive bioinformatic analysis to identify regulatory proteins in the recently annotated genome of the highly virulent AB5075 strain. In so doing, 243 transcription factors, 14 two-component systems (TCSs), 2 orphan response regulators, 1 hybrid TCS and 5 σ factors were found. A comparison of these elements between AB5075 and other clinical isolates, as well as a laboratory strain, led to the identification of several conserved regulatory elements, whilst at the same time uncovering regulators unique to hypervirulent strains. Lastly, by comparing regulatory elements compiled in this study to genes shown to be essential for AB5075 infection, we were able to highlight elements with a specific importance for pathogenic behaviour. Collectively, our work offers a unique insight into the regulatory network of A. baumannii strains, and provides insight into the evolution of hypervirulent lineages.

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Section: Resultsmentioning

confidence: 99%

“…Additionally, the ferric-uptake regulator (Fur) has been described as controlling expression of genes involved in siderophore production [21, 22]. A fourth TF, SoxR, is a MerR-like regulator governing transcription of the AbuO outer-membrane protein, which is important for resistance to osmotic and oxidative stress [23].…”

Section: Introductionmentioning

confidence: 99%

Towards the complete proteinaceous regulome of Acinetobacter baumannii

et al. 2017

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“…Due to the moderate inhibitory, but non-lethal effect of 200 μM DIP, this concentration was chosen to study transcriptional changes under iron limitation. Preliminary qRT-PCR was performed to confirm transcriptional adaptation in response to iron limitation by assaying the level of transcription of the ferric uptake regulator (FUR), which is known for auto-up-regulation when iron is limited [26]. A. baumannii grown in the presence of 200 μM DIP expressed FUR at levels increased more than 2-fold compared to cells grown under iron replete conditions (data not shown).…”

Section: Resultsmentioning

confidence: 99%

Investigation of the human pathogen Acinetobacter baumannii under iron limiting conditions

et al. 2011

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BackgroundIron acquisition systems are important virulence factors in pathogenic bacteria. To identify these systems in Acinetobacter baumannii, the transcriptomic response of the completely sequenced strain ATCC 17978 under iron limiting conditions was investigated using a genomic microarray that contained probes for all annotated open reading frames.ResultsUnder low iron conditions, transcription levels were more than 2-fold up-regulated for 463 genes, including 95 genes that were up-regulated more than 4-fold. Of particular significance, three siderophore biosynthesis gene clusters, including one novel cluster, were highly up-regulated. Binding sites for the ferric uptake regulator were identified in the promoter regions of many up-regulated genes, suggesting a prominent role for this regulator in the Acinetobacter iron acquisition response. Down-regulation under iron limitation was less dramatic as the transcription of only 202 genes varied more than 2-fold. Various genes involved in motility featured prominently amongst the genes down-regulated when iron was less readily available. Motility assays confirmed that these transcriptional changes are manifested at the phenotypic level. The siderophore biosynthesis gene clusters were further investigated by means of comparative genomic analysis of 10 sequenced Acinetobacter isolates. These analyses revealed important roles for mobile genetic elements in shaping the siderophore meditated iron acquisition mechanisms between different Acinetobacter strains.ConclusionsA. baumannii grown under iron limited conditions resulted in major transcriptional changes of not only many iron acquisition related genes, but also genes involved in other processes such as motility. Overall, this study showed that A. baumannii is well adaptable to growth in an environment which has limiting iron availability.

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“…These observations suggest that Ab-mediated iron acquisition may have an important role in the pathogenesis of A. baumannii infections. Moreover, Daniel et al (1999) reported that A. baumannii also possesses a Fur protein 63 % identical to that of Escherichia coli. In accordance with this, several Fur-target genes have recently been identified in this species (Echenique et al, 2001;Dorsey et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Identification and transcriptional organization of a gene cluster involved in biosynthesis and transport of acinetobactin, a siderophore produced by Acinetobacter baumannii ATCC 19606T

et al. 2004

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In order to assimilate iron, Acinetobacter baumannii ATCC 19606T produces a siderophore named acinetobactin (Ab) that is composed of equimolar quantities of 2,3-dihydroxybenzoic acid (DHBA), L-threonine and N-hydroxyhistamine. Application of the Fur titration assay system to A. baumannii genomic libraries, followed by further cloning of the regions surrounding the candidate genes, led to the identification of the Ab cluster, which harbours the genetic determinants necessary for the biosynthesis and transport of the siderophore. However, an entA homologue essential for DHBA biosynthesis was not found in this cluster. Functions of potential biosynthetic genes inferred by homology studies suggested that the precursors, DHBA, L-threonine and N-hydroxyhistamine, are linked in steps resembling those of bacterial non-ribosomal peptide synthesis to form Ab. Genes responsible for the two-step biosynthesis of N-hydroxyhistamine from histidine were also identified in this cluster. Their genetic organization suggests that five genes involved in the transport system of ferric Ab into the cell cytosol form an operon. Construction of disruptants of some selected genes followed by phenotypic analysis supported their predicted biological functions. Interestingly, three additional genes probably involved in the intracellular release of iron from ferric Ab and the secretion of nascent Ab are contained in this cluster. Primer extension and RT-PCR analyses suggested that the Ab cluster, which includes 18 genes, is organized in seven transcriptional units originating from respective Fur-regulated promoter-operator regions.

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Characterization of theAcinetobacter baumanniiFur regulator: cloning and sequencing of thefurhomolog gene

Cited by 32 publications

References 19 publications

Towards the complete proteinaceous regulome of Acinetobacter baumannii

Towards the complete proteinaceous regulome of Acinetobacter baumannii

Investigation of the human pathogen Acinetobacter baumannii under iron limiting conditions

Identification and transcriptional organization of a gene cluster involved in biosynthesis and transport of acinetobactin, a siderophore produced by Acinetobacter baumannii ATCC 19606T

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